Conventional textile implantable prostheses are manufactured using yarns made of biocompatible and biostable material. One polymeric material widely used in conventional implants is polyethylene terephthalate (PET.) This material has been found to be especially useful in vascular grafts and stent grafts, as well as other textile implants such as patches, surgical mesh, sutures, filters, ligaments and the like. Further applications of PET include surgically implanted vascular grafts and endoluminal vascular grafts implanted by minimally invasive procedures.
Prostheses desirably exhibit long term wear and kink resistance so that they do not have to replaced as often. Many current designs include a metal stent attached to an endoluminal graft to form a composite device for implantation. Typically, the fabrics used in these types of textile constructions are subjected t to strenuous conditions such as constant rubbing against the stent during pulsation of blood. Such abrasive forces can result in weakening of current PET textile grafts which can result in loss of structural integrity and in extreme cases graft failure. Additionally, in applications involving peripheral vessels, current textile fabrics, such as those made from PET, are less kink resistant than desired. This may especially be a problem for prostheses used in smaller passageways such as those found in legs or children. Thus, there is a need for more durable fabrics that are capable of being incorporated into vascular prostheses for use in peripheral vessels.
Prostheses are desirably implanted into the body without introducing sources of infection in the body. Thus, in addition to being strong and durable, textile materials used for implantable devices must also be able to undergo sterilization procedures. To minimize infectious sources introduced by the implantation of prostheses, sterilization methods, such as gas sterilization, have been utilized. Unfortunately, gas sterilization methods do not guarantee that virulent strains of bacteria and viruses will be killed. The emergence of antibiotic resistant strains of bacteria have made sterilization an even more important issue. Traditional prostheses, such as those manufactured with PET fabrics, cannot tolerate more powerful methods of sterilization, such as radiation or steam sterilization, without risking degradation of the fabric. These degradative effects might seem to be minimal at first, but over the lifetime of its implant can prove to be significant enough to compromise the structural integrity and stability of the textile in vivo. Thus, it would be desirable to be able to manufacture prostheses that can be treated with more powerful sterilization methods, such as steam sterilization, prior to implantation to eliminate possible sources of infection from the prosthesis. Steam sterilization is also desirable in emergency situations when quick implantation of the graft is necessary or more sophisticated methods are not available.
Accordingly, it is desirable to provide an implantable textile prostheses with improved chemical and mechanical properties so that the prostheses will overcome the deficiencies of the currently available textile prostheses. In particular, it would be desirable to develop a new implantable textile prosthesis having higher modulus and tensile strength, enhanced abrasion resistance, higher thermal and radiation resistance, self-sealing properties and greater hydrolytic stability.